drivers/scsi/hosts.c

   1 /*
   2  *  hosts.c Copyright (C) 1992 Drew Eckhardt
   3  *          Copyright (C) 1993, 1994, 1995 Eric Youngdale
   4  *          Copyright (C) 2002-2003 Christoph Hellwig
   5  *
   6  *  mid to lowlevel SCSI driver interface
   7  *      Initial versions: Drew Eckhardt
   8  *      Subsequent revisions: Eric Youngdale
   9  *
  10  *  <drew@colorado.edu>
  11  *
  12  *  Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
  13  *  Added QLOGIC QLA1280 SCSI controller kernel host support.
  14  *     August 4, 1999 Fred Lewis, Intel DuPont
  15  *
  16  *  Updated to reflect the new initialization scheme for the higher
  17  *  level of scsi drivers (sd/sr/st)
  18  *  September 17, 2000 Torben Mathiasen <tmm@image.dk>
  19  *
  20  *  Restructured scsi_host lists and associated functions.
  21  *  September 04, 2002 Mike Anderson (andmike@us.ibm.com)
  22  */
  23
  24 #include <linux/module.h>
  25 #include <linux/blkdev.h>
  26 #include <linux/kernel.h>
  27 #include <linux/slab.h>
  28 #include <linux/kthread.h>
  29 #include <linux/string.h>
  30 #include <linux/mm.h>
  31 #include <linux/init.h>
  32 #include <linux/completion.h>
  33 #include <linux/transport_class.h>
  34 #include <linux/platform_device.h>
  35 #include <linux/pm_runtime.h>
  36
  37 #include <scsi/scsi_device.h>
  38 #include <scsi/scsi_host.h>
  39 #include <scsi/scsi_transport.h>
  40
  41 #include "scsi_priv.h"
  42 #include "scsi_logging.h"
  43
  44
  45 static atomic_t scsi_host_next_hn = ATOMIC_INIT(0);     /* host_no for next new host */
  46
  47
  48 static void scsi_host_cls_release(struct device *dev)
  49 {
  50         put_device(&class_to_shost(dev)->shost_gendev);
  51 }
  52
  53 static struct class shost_class = {
  54         .name           = "scsi_host",
  55         .dev_release    = scsi_host_cls_release,
  56 };
  57
  58 /**
  59  *      scsi_host_set_state - Take the given host through the host state model.
  60  *      @shost: scsi host to change the state of.
  61  *      @state: state to change to.
  62  *
  63  *      Returns zero if unsuccessful or an error if the requested
  64  *      transition is illegal.
  65  **/
  66 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
  67 {
  68         enum scsi_host_state oldstate = shost->shost_state;
  69
  70         if (state == oldstate)
  71                 return 0;
  72
  73         switch (state) {
  74         case SHOST_CREATED:
  75                 /* There are no legal states that come back to
  76                  * created.  This is the manually initialised start
  77                  * state */
  78                 goto illegal;
  79
  80         case SHOST_RUNNING:
  81                 switch (oldstate) {
  82                 case SHOST_CREATED:
  83                 case SHOST_RECOVERY:
  84                         break;
  85                 default:
  86                         goto illegal;
  87                 }
  88                 break;
  89
  90         case SHOST_RECOVERY:
  91                 switch (oldstate) {
  92                 case SHOST_RUNNING:
  93                         break;
  94                 default:
  95                         goto illegal;
  96                 }
  97                 break;
  98
  99         case SHOST_CANCEL:
 100                 switch (oldstate) {
 101                 case SHOST_CREATED:
 102                 case SHOST_RUNNING:
 103                 case SHOST_CANCEL_RECOVERY:
 104                         break;
 105                 default:
 106                         goto illegal;
 107                 }
 108                 break;
 109
 110         case SHOST_DEL:
 111                 switch (oldstate) {
 112                 case SHOST_CANCEL:
 113                 case SHOST_DEL_RECOVERY:
 114                         break;
 115                 default:
 116                         goto illegal;
 117                 }
 118                 break;
 119
 120         case SHOST_CANCEL_RECOVERY:
 121                 switch (oldstate) {
 122                 case SHOST_CANCEL:
 123                 case SHOST_RECOVERY:
 124                         break;
 125                 default:
 126                         goto illegal;
 127                 }
 128                 break;
 129
 130         case SHOST_DEL_RECOVERY:
 131                 switch (oldstate) {
 132                 case SHOST_CANCEL_RECOVERY:
 133                         break;
 134                 default:
 135                         goto illegal;
 136                 }
 137                 break;
 138         }
 139         shost->shost_state = state;
 140         return 0;
 141
 142  illegal:
 143         SCSI_LOG_ERROR_RECOVERY(1,
 144                                 shost_printk(KERN_ERR, shost,
 145                                              "Illegal host state transition"
 146                                              "%s->%s\n",
 147                                              scsi_host_state_name(oldstate),
 148                                              scsi_host_state_name(state)));
 149         return -EINVAL;
 150 }
 151 EXPORT_SYMBOL(scsi_host_set_state);
 152
 153 /**
 154  * scsi_remove_host - remove a scsi host
 155  * @shost:      a pointer to a scsi host to remove
 156  **/
 157 void scsi_remove_host(struct Scsi_Host *shost)
 158 {
 159         unsigned long flags;
 160
 161         mutex_lock(&shost->scan_mutex);
 162         spin_lock_irqsave(shost->host_lock, flags);
 163         if (scsi_host_set_state(shost, SHOST_CANCEL))
 164                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
 165                         spin_unlock_irqrestore(shost->host_lock, flags);
 166                         mutex_unlock(&shost->scan_mutex);
 167                         return;
 168                 }
 169         spin_unlock_irqrestore(shost->host_lock, flags);
 170
 171         scsi_autopm_get_host(shost);
 172         flush_workqueue(shost->tmf_work_q);
 173         scsi_forget_host(shost);
 174         mutex_unlock(&shost->scan_mutex);
 175         scsi_proc_host_rm(shost);
 176
 177         spin_lock_irqsave(shost->host_lock, flags);
 178         if (scsi_host_set_state(shost, SHOST_DEL))
 179                 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
 180         spin_unlock_irqrestore(shost->host_lock, flags);
 181
 182         transport_unregister_device(&shost->shost_gendev);
 183         device_unregister(&shost->shost_dev);
 184         device_del(&shost->shost_gendev);
 185 }
 186 EXPORT_SYMBOL(scsi_remove_host);
 187
 188 /**
 189  * scsi_add_host_with_dma - add a scsi host with dma device
 190  * @shost:      scsi host pointer to add
 191  * @dev:        a struct device of type scsi class
 192  * @dma_dev:    dma device for the host
 193  *
 194  * Note: You rarely need to worry about this unless you're in a
 195  * virtualised host environments, so use the simpler scsi_add_host()
 196  * function instead.
 197  *
 198  * Return value:
 199  *      0 on success / != 0 for error
 200  **/
 201 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
 202                            struct device *dma_dev)
 203 {
 204         struct scsi_host_template *sht = shost->hostt;
 205         int error = -EINVAL;
 206
 207         shost_printk(KERN_INFO, shost, "%s\n",
 208                         sht->info ? sht->info(shost) : sht->name);
 209
 210         if (!shost->can_queue) {
 211                 shost_printk(KERN_ERR, shost,
 212                              "can_queue = 0 no longer supported\n");
 213                 goto fail;
 214         }
 215
 216         if (shost_use_blk_mq(shost)) {
 217                 error = scsi_mq_setup_tags(shost);
 218                 if (error)
 219                         goto fail;
 220         }
 221
 222         /*
 223          * Note that we allocate the freelist even for the MQ case for now,
 224          * as we need a command set aside for scsi_reset_provider.  Having
 225          * the full host freelist and one command available for that is a
 226          * little heavy-handed, but avoids introducing a special allocator
 227          * just for this.  Eventually the structure of scsi_reset_provider
 228          * will need a major overhaul.
 229          */
 230         error = scsi_setup_command_freelist(shost);
 231         if (error)
 232                 goto out_destroy_tags;
 233
 234
 235         if (!shost->shost_gendev.parent)
 236                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
 237         if (!dma_dev)
 238                 dma_dev = shost->shost_gendev.parent;
 239
 240         shost->dma_dev = dma_dev;
 241
 242         error = device_add(&shost->shost_gendev);
 243         if (error)
 244                 goto out_destroy_freelist;
 245
 246         pm_runtime_set_active(&shost->shost_gendev);
 247         pm_runtime_enable(&shost->shost_gendev);
 248         device_enable_async_suspend(&shost->shost_gendev);
 249
 250         scsi_host_set_state(shost, SHOST_RUNNING);
 251         get_device(shost->shost_gendev.parent);
 252
 253         device_enable_async_suspend(&shost->shost_dev);
 254
 255         error = device_add(&shost->shost_dev);
 256         if (error)
 257                 goto out_del_gendev;
 258
 259         get_device(&shost->shost_gendev);
 260
 261         if (shost->transportt->host_size) {
 262                 shost->shost_data = kzalloc(shost->transportt->host_size,
 263                                          GFP_KERNEL);
 264                 if (shost->shost_data == NULL) {
 265                         error = -ENOMEM;
 266                         goto out_del_dev;
 267                 }
 268         }
 269
 270         if (shost->transportt->create_work_queue) {
 271                 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
 272                          "scsi_wq_%d", shost->host_no);
 273                 shost->work_q = create_singlethread_workqueue(
 274                                         shost->work_q_name);
 275                 if (!shost->work_q) {
 276                         error = -EINVAL;
 277                         goto out_free_shost_data;
 278                 }
 279         }
 280
 281         error = scsi_sysfs_add_host(shost);
 282         if (error)
 283                 goto out_destroy_host;
 284
 285         scsi_proc_host_add(shost);
 286         return error;
 287
 288  out_destroy_host:
 289         if (shost->work_q)
 290                 destroy_workqueue(shost->work_q);
 291  out_free_shost_data:
 292         kfree(shost->shost_data);
 293  out_del_dev:
 294         device_del(&shost->shost_dev);
 295  out_del_gendev:
 296         device_del(&shost->shost_gendev);
 297  out_destroy_freelist:
 298         scsi_destroy_command_freelist(shost);
 299  out_destroy_tags:
 300         if (shost_use_blk_mq(shost))
 301                 scsi_mq_destroy_tags(shost);
 302  fail:
 303         return error;
 304 }
 305 EXPORT_SYMBOL(scsi_add_host_with_dma);
 306
 307 static void scsi_host_dev_release(struct device *dev)
 308 {
 309         struct Scsi_Host *shost = dev_to_shost(dev);
 310         struct device *parent = dev->parent;
 311         struct request_queue *q;
 312         void *queuedata;
 313
 314         scsi_proc_hostdir_rm(shost->hostt);
 315
 316         if (shost->tmf_work_q)
 317                 destroy_workqueue(shost->tmf_work_q);
 318         if (shost->ehandler)
 319                 kthread_stop(shost->ehandler);
 320         if (shost->work_q)
 321                 destroy_workqueue(shost->work_q);
 322         q = shost->uspace_req_q;
 323         if (q) {
 324                 queuedata = q->queuedata;
 325                 blk_cleanup_queue(q);
 326                 kfree(queuedata);
 327         }
 328
 329         if (shost->shost_state == SHOST_CREATED) {
 330                 /*
 331                  * Free the shost_dev device name here if scsi_host_alloc()
 332                  * and scsi_host_put() have been called but neither
 333                  * scsi_host_add() nor scsi_host_remove() has been called.
 334                  * This avoids that the memory allocated for the shost_dev
 335                  * name is leaked.
 336                  */
 337                 kfree(dev_name(&shost->shost_dev));
 338         }
 339
 340         scsi_destroy_command_freelist(shost);
 341         if (shost_use_blk_mq(shost)) {
 342                 if (shost->tag_set.tags)
 343                         scsi_mq_destroy_tags(shost);
 344         } else {
 345                 if (shost->bqt)
 346                         blk_free_tags(shost->bqt);
 347         }
 348
 349         kfree(shost->shost_data);
 350
 351         if (parent)
 352                 put_device(parent);
 353         kfree(shost);
 354 }
 355
 356 static int shost_eh_deadline = -1;
 357
 358 module_param_named(eh_deadline, shost_eh_deadline, int, S_IRUGO|S_IWUSR);
 359 MODULE_PARM_DESC(eh_deadline,
 360                  "SCSI EH timeout in seconds (should be between 0 and 2^31-1)");
 361
 362 static struct device_type scsi_host_type = {
 363         .name =         "scsi_host",
 364         .release =      scsi_host_dev_release,
 365 };
 366
 367 /**
 368  * scsi_host_alloc - register a scsi host adapter instance.
 369  * @sht:        pointer to scsi host template
 370  * @privsize:   extra bytes to allocate for driver
 371  *
 372  * Note:
 373  *      Allocate a new Scsi_Host and perform basic initialization.
 374  *      The host is not published to the scsi midlayer until scsi_add_host
 375  *      is called.
 376  *
 377  * Return value:
 378  *      Pointer to a new Scsi_Host
 379  **/
 380 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 381 {
 382         struct Scsi_Host *shost;
 383         gfp_t gfp_mask = GFP_KERNEL;
 384
 385         if (sht->unchecked_isa_dma && privsize)
 386                 gfp_mask |= __GFP_DMA;
 387
 388         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 389         if (!shost)
 390                 return NULL;
 391
 392         shost->host_lock = &shost->default_lock;
 393         spin_lock_init(shost->host_lock);
 394         shost->shost_state = SHOST_CREATED;
 395         INIT_LIST_HEAD(&shost->__devices);
 396         INIT_LIST_HEAD(&shost->__targets);
 397         INIT_LIST_HEAD(&shost->eh_cmd_q);
 398         INIT_LIST_HEAD(&shost->starved_list);
 399         init_waitqueue_head(&shost->host_wait);
 400         mutex_init(&shost->scan_mutex);
 401
 402         /*
 403          * subtract one because we increment first then return, but we need to
 404          * know what the next host number was before increment
 405          */
 406         shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1;
 407         shost->dma_channel = 0xff;
 408
 409         /* These three are default values which can be overridden */
 410         shost->max_channel = 0;
 411         shost->max_id = 8;
 412         shost->max_lun = 8;
 413
 414         /* Give each shost a default transportt */
 415         shost->transportt = &blank_transport_template;
 416
 417         /*
 418          * All drivers right now should be able to handle 12 byte
 419          * commands.  Every so often there are requests for 16 byte
 420          * commands, but individual low-level drivers need to certify that
 421          * they actually do something sensible with such commands.
 422          */
 423         shost->max_cmd_len = 12;
 424         shost->hostt = sht;
 425         shost->this_id = sht->this_id;
 426         shost->can_queue = sht->can_queue;
 427         shost->sg_tablesize = sht->sg_tablesize;
 428         shost->sg_prot_tablesize = sht->sg_prot_tablesize;
 429         shost->cmd_per_lun = sht->cmd_per_lun;
 430         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 431         shost->use_clustering = sht->use_clustering;
 432         shost->no_write_same = sht->no_write_same;
 433
 434         if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
 435                 shost->eh_deadline = -1;
 436         else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
 437                 shost_printk(KERN_WARNING, shost,
 438                              "eh_deadline %u too large, setting to %u\n",
 439                              shost_eh_deadline, INT_MAX / HZ);
 440                 shost->eh_deadline = INT_MAX;
 441         } else
 442                 shost->eh_deadline = shost_eh_deadline * HZ;
 443
 444         if (sht->supported_mode == MODE_UNKNOWN)
 445                 /* means we didn't set it ... default to INITIATOR */
 446                 shost->active_mode = MODE_INITIATOR;
 447         else
 448                 shost->active_mode = sht->supported_mode;
 449
 450         if (sht->max_host_blocked)
 451                 shost->max_host_blocked = sht->max_host_blocked;
 452         else
 453                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 454
 455         /*
 456          * If the driver imposes no hard sector transfer limit, start at
 457          * machine infinity initially.
 458          */
 459         if (sht->max_sectors)
 460                 shost->max_sectors = sht->max_sectors;
 461         else
 462                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 463
 464         /*
 465          * assume a 4GB boundary, if not set
 466          */
 467         if (sht->dma_boundary)
 468                 shost->dma_boundary = sht->dma_boundary;
 469         else
 470                 shost->dma_boundary = 0xffffffff;
 471
 472         shost->use_blk_mq = scsi_use_blk_mq && !shost->hostt->disable_blk_mq;
 473
 474         device_initialize(&shost->shost_gendev);
 475         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
 476         shost->shost_gendev.bus = &scsi_bus_type;
 477         shost->shost_gendev.type = &scsi_host_type;
 478
 479         device_initialize(&shost->shost_dev);
 480         shost->shost_dev.parent = &shost->shost_gendev;
 481         shost->shost_dev.class = &shost_class;
 482         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
 483         shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
 484
 485         shost->ehandler = kthread_run(scsi_error_handler, shost,
 486                         "scsi_eh_%d", shost->host_no);
 487         if (IS_ERR(shost->ehandler)) {
 488                 shost_printk(KERN_WARNING, shost,
 489                         "error handler thread failed to spawn, error = %ld\n",
 490                         PTR_ERR(shost->ehandler));
 491                 goto fail_kfree;
 492         }
 493
 494         shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
 495                                             WQ_UNBOUND | WQ_MEM_RECLAIM,
 496                                            1, shost->host_no);
 497         if (!shost->tmf_work_q) {
 498                 shost_printk(KERN_WARNING, shost,
 499                              "failed to create tmf workq\n");
 500                 goto fail_kthread;
 501         }
 502         scsi_proc_hostdir_add(shost->hostt);
 503         return shost;
 504
 505  fail_kthread:
 506         kthread_stop(shost->ehandler);
 507  fail_kfree:
 508         kfree(shost);
 509         return NULL;
 510 }
 511 EXPORT_SYMBOL(scsi_host_alloc);
 512
 513 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
 514 {
 515         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
 516
 517         if (!sht->detect) {
 518                 printk(KERN_WARNING "scsi_register() called on new-style "
 519                                     "template for driver %s\n", sht->name);
 520                 dump_stack();
 521         }
 522
 523         if (shost)
 524                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
 525         return shost;
 526 }
 527 EXPORT_SYMBOL(scsi_register);
 528
 529 void scsi_unregister(struct Scsi_Host *shost)
 530 {
 531         list_del(&shost->sht_legacy_list);
 532         scsi_host_put(shost);
 533 }
 534 EXPORT_SYMBOL(scsi_unregister);
 535
 536 static int __scsi_host_match(struct device *dev, const void *data)
 537 {
 538         struct Scsi_Host *p;
 539         const unsigned short *hostnum = data;
 540
 541         p = class_to_shost(dev);
 542         return p->host_no == *hostnum;
 543 }
 544
 545 /**
 546  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 547  * @hostnum:    host number to locate
 548  *
 549  * Return value:
 550  *      A pointer to located Scsi_Host or NULL.
 551  *
 552  *      The caller must do a scsi_host_put() to drop the reference
 553  *      that scsi_host_get() took. The put_device() below dropped
 554  *      the reference from class_find_device().
 555  **/
 556 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 557 {
 558         struct device *cdev;
 559         struct Scsi_Host *shost = NULL;
 560
 561         cdev = class_find_device(&shost_class, NULL, &hostnum,
 562                                  __scsi_host_match);
 563         if (cdev) {
 564                 shost = scsi_host_get(class_to_shost(cdev));
 565                 put_device(cdev);
 566         }
 567         return shost;
 568 }
 569 EXPORT_SYMBOL(scsi_host_lookup);
 570
 571 /**
 572  * scsi_host_get - inc a Scsi_Host ref count
 573  * @shost:      Pointer to Scsi_Host to inc.
 574  **/
 575 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 576 {
 577         if ((shost->shost_state == SHOST_DEL) ||
 578                 !get_device(&shost->shost_gendev))
 579                 return NULL;
 580         return shost;
 581 }
 582 EXPORT_SYMBOL(scsi_host_get);
 583
 584 /**
 585  * scsi_host_put - dec a Scsi_Host ref count
 586  * @shost:      Pointer to Scsi_Host to dec.
 587  **/
 588 void scsi_host_put(struct Scsi_Host *shost)
 589 {
 590         put_device(&shost->shost_gendev);
 591 }
 592 EXPORT_SYMBOL(scsi_host_put);
 593
 594 int scsi_init_hosts(void)
 595 {
 596         return class_register(&shost_class);
 597 }
 598
 599 void scsi_exit_hosts(void)
 600 {
 601         class_unregister(&shost_class);
 602 }
 603
 604 int scsi_is_host_device(const struct device *dev)
 605 {
 606         return dev->type == &scsi_host_type;
 607 }
 608 EXPORT_SYMBOL(scsi_is_host_device);
 609
 610 /**
 611  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 612  * @shost:      Pointer to Scsi_Host.
 613  * @work:       Work to queue for execution.
 614  *
 615  * Return value:
 616  *      1 - work queued for execution
 617  *      0 - work is already queued
 618  *      -EINVAL - work queue doesn't exist
 619  **/
 620 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 621 {
 622         if (unlikely(!shost->work_q)) {
 623                 shost_printk(KERN_ERR, shost,
 624                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 625                         "when no workqueue created.\n", shost->hostt->name);
 626                 dump_stack();
 627
 628                 return -EINVAL;
 629         }
 630
 631         return queue_work(shost->work_q, work);
 632 }
 633 EXPORT_SYMBOL_GPL(scsi_queue_work);
 634
 635 /**
 636  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 637  * @shost:      Pointer to Scsi_Host.
 638  **/
 639 void scsi_flush_work(struct Scsi_Host *shost)
 640 {
 641         if (!shost->work_q) {
 642                 shost_printk(KERN_ERR, shost,
 643                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 644                         "when no workqueue created.\n", shost->hostt->name);
 645                 dump_stack();
 646                 return;
 647         }
 648
 649         flush_workqueue(shost->work_q);
 650 }
 651 EXPORT_SYMBOL_GPL(scsi_flush_work);